Millions washed away after warning ignored

Tony Moore

An Ipswich businessman who lost millions in January's floods after asking Seqwater to purge the Wivenhoe Dam a month earlier says he feels vindicated by the flood inquiry's findings.

Darren Zanow lost $9 million from his gravel and development business after telling Seqwater on December 10 they should drop Wivenhoe Dam to 70 or 80 per cent capacity to give Ipswich and Brisbane extra flood protection.

Yesterday, Justice Catherine Holmes's commission of inquiry into the floods released its first reportinto the disaster, recommending Wivenhoe Dam be dropped to 75 per capacity in a "big wet".

"I feel that I have been proven right by a commission that cost $15 million that needn't have happened," the Ipswich businessman said.

Advertisement

Mr Zanow, his brother Brad and a group of irrigators met three senior Seqwater engineers, including Wivenhoe's dam manager Rob Drury, on December 10 and strongly suggested Seqwater lower the level of water in the dam.

Quarry operator Mr Zanow said he had pressed Seqwater for most of 2010 on the impact of any water releases from Wivenhoe.

He argued Seqwater should release the water slowly from the dam, certainly after their meeting on December 10, and not wait for a month to release water on January 9.

Three days later, on December 13, Seqwater gave advice to the Water Grid Manager, who told Natural Resources Minister Stephen Robertson the dam level could be reduced but it would not have any major impact on flood levels.

The brothers have run a quarry business on the Brisbane and Bremer rivers about 18 kilometres downstream of Wivenhoe Dam for many years.

"The Mid-Brisbane Irrigators had a meeting with the dam engineers at Wivenhoe on the 10th of December," he said.

"We said 'Have you ever considered reducing the full storage level of the dam down from 100 per cent to around 70 per cent to 80 per cent".

"They said 'Well we have, but it would make no difference in a big event."

Mr Zanow said he and his brother had calculated the impact last October based on Wivenhoe Dam surface area and the saturation of the ground at the time.

"If Wivenhoe is 100 per cent full, we have a flood mitigation of around 1 million megalitres (Queensland's Water Grid information shows 1.45 million megalitres)," he said.

"If you equate all that out, if you get seven inches [18cm] of rain over that catchment, you run out of flood storage capacity."

Mr Zanow said he and his brother believed Seqwater's engineers and senior management were not familiar enough with the issues raised by local farmers.

"We just didn't feel that they had their finger on the pulse about the potential for flooding and the amount of water that they would have to manage if we had a major event.

"I mean in the 1974 flood, in seven days, they had 24 inches [61cm] of rain in the catchment.

"So we're saying. 'seven inches of rain and we have got this flood mitigation compartment of this dam full."

The brothers again pressed the point with Seqwater.

They based their case on Wivenhoe's catchment receiving 25cm of rain.

"If it was 70 per cent and 80 per cent you would be able to handle that a lot better," said Mr Zanow.

"And the chance of getting 10 inches of rain was about one in 10, while the chance of seven inches was about one in two at that time."

Mr Zanow said Seqwater faced no problems physically reducing that amount of water.

"After the flood (in February) they pulled the dam back from 190 per cent (including the flood mitigation section) to 100 per cent in one week," he said.

"Then they pulled it back from 100 per cent to around 76 per cent and that took about 11 days and it didn't affect anyone."

Mr Zanow said it was not a "big deal" to pull a dam back from 100 per cent to 75 per cent in two weeks.

"That is easy. It is easy," he said. "But they didn't listen to us. They didn't listen."

Mr Zanow said engineering tests since the flood showed the dam wall was safe.

However he said authorities were putting together an expensive case study to concrete much of Wivenhoe's earth wall.

Those steps would give the dam extra flood storage.

"And I would like to see the engineering study that was done of the dam wall since the flood," he said.

Mr Zanow said he took out flood insurance for his business in September 2010.

"And the reason I did that was because I didn't have confidence in the water being released from Wivenhoe Dam in a way that would protect my business," he said.

7 comments so far

Damned if you do damned if you dont....

Commenter

Popeye

Location

Moggil Ferry

Date and time

August 02, 2011, 8:34AM

This man runs a business which has yet to move to the metric system? What's all this inches business?He dug a hole (quarry) and it filled with water when it rained. Is anyone surprised? And, he miscalcualted the dam capacity by 45 million meglitres?And, he thought 25% of that could be released (during the same 'big wet') in two weeks and not have any impact on flooding? Please, everyone is an expert when they have no responsibility.

Commenter

Leo

Location

Priest Gully

Date and time

August 02, 2011, 8:36AM

I think the dam is there to serve all Brisbane people not just the 20,000 households and however many businesses that flooded.

It is also providing drinking water to a massive population. I don't agree with dropping the level to 75%. We let out tens of millions of dollars worth of water.

The dam did its job, Flood mitigation. It is not flood prevention, nothing can do that. There were three bigger floods in the last 150 years, we got off lightly thanks to the dam.

If people are lloking for someone to blame they should blame themselves. The 74 flood levels were easily available and the council published them on their web site a few years ago.

Commenter

Phantom

Location

Brisbane

Date and time

August 02, 2011, 11:39AM

Ipswich is on the Bremer River.Wivenhoe is on the Brisbane River.

Once all the floodgates were open, which is what would have been the case if Wivenhoe was 100%, 75% or even 50% due to the rapidity of the rise, the flow of water in the Brisbane River would have been exactly the same and would have caused exactly the same back-up of water into teh Bremer River which would have lead to exactly the same level of flooding in Ipswich.

Commenter

Goresh

Location

Brisbane

Date and time

August 02, 2011, 1:04PM

"We let out tens of millions of dollars worth of water""

Phantom, so consider what the alternative was; we 'saved' millions of dollars worth of water and instead end up with millions of dollars worth of damage.

I don't think anybody is in the 'flood prevention' mindset. As you say that can't happen. However, had better decisions been made, we could have even got off even lighter. Using the decisions made during the 2011 floods, we wouldn't have got off at all had the flood been at prior levels.

Somebody is always on the edge of the flood event; one house in the street is flooded and the next isn't. Decisions to empty earlier would have had a *great* impact on that one family; isn't that worth it? The benefits are there for the individual, community, insurance companies and the economy in general. one less flooded house is invaluable.

This is always going to be the largest lesson for us all.

Commenter

dallas

Location

west end

Date and time

August 02, 2011, 7:10PM

It is very obvious to anyone reading this article that the gentleman has been vindicated by the Commission's findings. Why do people continue to put others down just because it doesn't suit their own agenda....and for your information many people use both forms of measuring because we had the pleasure (or displeasure) of growing up with the 2 systems. (Metric quantities were quoted as well - unless you can't read English!). You can always buy bottled water but flood management is an entirely different matter. Agree with Popeye!!

Commenter

spollydolly

Date and time

August 03, 2011, 2:41AM

Mr Zanow is quite right. A simple 'back of the envelope' calculation shows what could have been done. And after all that was what the dam was designed to do.

The trouble was the dam wasn't operated properly because the government had been incessantly earbashed by doomsayers like the incompetent Flannery to believe that every drop must be saved because it will never rain again. The dam was too full to serve its flood mitigation role and there wasn't enough time to safely recover from this very basic political error.